One of the issues I've heard in regards to a counter cyber attack by the US is it will reveal our capabilities. The NORKs (or whoever) would do the same type of analysis that we do when someone hacks into one of our computer systems. You find where the vulnerabilities are and a way to stop the next attack.
Would we/should we use that option now or wait until a far more serious attack occurred?
Would it make you nervous if I told you that private hackers and the Government have been more and more cozy lately?
The head of the NSA and CyberCom was a guest speaker at DefCon and BlackHat this year and last.
They wouldn't have to reveal the government's capability when they can elicit the help of the hacker community at large.
